Jugement rendu par la Haute-Cour de justice, le premier pluviôse l'an V, au nom du peuple français... ([Reprod.]) / [signé : J. B. Jalbert, greffier]

Collection : Les archives de la Révolution française ; 6.2.1769

The ATPase activity of RecA is needed to push the DNA strand exchange through heterologous regions.

The role of ATP hydrolysis during the RecA-mediated recombination reaction is addressed in this paper. Recent studies indicated that the RecA-promoted DNA strand exchange between completely homologous double- and single-stranded DNA can be very efficient in the absence of ATP hydrolysis. In this work we demonstrate that the energy derived from the ATP hydrolysis is strictly needed to drive the DNA strand exchange through the regions where the interacting DNA molecules are not in a homologous register. Therefore, in addition to the role of the ATP hydrolysis in promoting the dissociation of RecA from the products of the recombination reaction, as described earlier, ATP hydrolysis also plays a crucial role in the actual process of strand exchange, provided that the lack of homologous register obstructs the process of branch migration.

V. Stanley, Blatty, amiral [Charles Edward] Madden : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 55158

Identification of key amino acids of the mouse mammary tumor virus superantigen involved in the specific interaction with T-cell receptor V(beta) domains.

Mouse mammary tumor virus (MMTV) is a retrovirus encoding a superantigen that is recognized in association with major histocompatibility complex class II by the variable region of the beta chain (V(beta)) of the T-cell receptor. The C-terminal 30 to 40 amino acids of the superantigen of different MMTVs display high sequence variability that correlates with the recognition of particular T-cell receptor V(beta) chains. Interestingly, MMTV(SIM) and mtv-8 superantigens are highly homologous but have nonoverlapping T-cell receptor V(beta) specificities. To determine the importance of these few differences for specific V(beta) interaction, we studied superantigen responses in mice to chimeric and mutant MMTV(SIM) and mtv-8 superantigens expressed by recombinant vaccinia viruses. We show that only a few changes (two to six residues) within the C terminus are necessary to modify superantigen recognition by specific V(beta)s. Thus, the introduction of the MMTV(SIM) residues 314-315 into the mtv-8 superantigen greatly decreased its V(beta)12 reactivity without gain of MMTV(SIM)-specific function. The introduction of MMTV(SIM)-specific residues 289 to 295, however, induced a recognition pattern that was a mixture of MMTV(SIM)- and mtv-8-specific V(beta) reactivities: both weak MMTV(SIM)-specific V(beta)4 and full mtv-8-specific V(beta)11 recognition were observed while V(beta)12 interaction was lost. The combination of the two MMTV(SIM)-specific regions in the mtv-8 superantigen established normal MMTV(SIM)-specific V(beta)4 reactivity and completely abolished mtv-8-specific V(beta)5, -11, and -12 interactions. These new functional superantigens with mixed V(beta) recognition patterns allowed us to precisely delineate sites relevant for molecular interactions between the SIM or mtv-8 superantigen and the T-cell receptor V(beta) domain within the 30 C-terminal residues of the viral superantigen.

La guerre : récit épisodique d'un siège au XVIe siècle / par Carlo Du Monge,... ; illustrations de V. Poirson. suivi de : Le secret du fer / par J. Protche de Viville,.... Les Lansquenets / par Ernest d'Hervilly,...

Comprend : Les Lansquenets ; Le secret du fer